/*
 * Copyright (C) 2012 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package ux.com.squareup.okhttp.internal.http;

import ux.com.squareup.okhttp.internal.okio.Sink;
import ux.com.squareup.okhttp.internal.okio.Source;

import java.io.IOException;
import java.net.CacheRequest;

interface Transport {
    /**
     * The timeout to use while discarding a stream of input data. Since this is
     * used for connection reuse, this timeout should be significantly less than
     * the time it takes to establish a new connection.
     */
    int DISCARD_STREAM_TIMEOUT_MILLIS = 100;

    /**
     * Returns an output stream where the request body can be written. The
     * returned stream will of one of two types:
     * <ul>
     * <li><strong>Direct.</strong> Bytes are written to the socket and
     * forgotten. This is most efficient, particularly for large request
     * bodies. The returned stream may be buffered; the caller must call
     * {@link #flushRequest} before reading the response.</li>
     * <li><strong>Buffered.</strong> Bytes are written to an in memory
     * buffer, and must be explicitly flushed with a call to {@link
     * #writeRequestBody}. This allows HTTP authorization (401, 407)
     * responses to be retransmitted transparently.</li>
     * </ul>
     */
    // TODO: don't bother retransmitting the request body? It's quite a corner
    // case and there's uncertainty whether Firefox or Chrome do this
    Sink createRequestBody(Request request) throws IOException;

    /**
     * This should update the HTTP engine's sentRequestMillis field.
     */
    void writeRequestHeaders(Request request) throws IOException;

    /**
     * Sends the request body returned by {@link #createRequestBody} to the
     * remote peer.
     */
    void writeRequestBody(RetryableSink requestBody) throws IOException;

    /**
     * Flush the request body to the underlying socket.
     */
    void flushRequest() throws IOException;

    /**
     * Read response headers and update the cookie manager.
     */
    Response.Builder readResponseHeaders() throws IOException;

    /**
     * Notify the transport that no response body will be read.
     */
    void emptyTransferStream() throws IOException;

    // TODO: make this the content stream?
    Source getTransferStream(CacheRequest cacheRequest) throws IOException;

    /**
     * Configures the response body to pool or close the socket connection when
     * the response body is closed.
     */
    void releaseConnectionOnIdle() throws IOException;

    void disconnect(HttpEngine engine) throws IOException;

    /**
     * Returns true if the socket connection held by this transport can be reused
     * for a follow-up exchange.
     */
    boolean canReuseConnection();
}
